Pleated or folded catheter-mounted balloon

ABSTRACT

A catheter-mounted balloon includes an inflatable chamber defining a volume expandable from a deflated state to an inflated state, the inflatable chamber having a distal transition portion, a proximal transition portion, and a cylindrical body portion disposed between the distal transition portion and the proximal transition portion. The cylindrical body portion of the inflatable chamber includes a pleat zone having a pleat when the inflatable chamber is in the deflated state. The catheter-mounted balloon further includes an electrode disposed along a wall of the inflatable chamber. The pleat traverses the electrode such that is electrode is pleated as well.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 61/877,923, filed on Sep. 13, 2013, entitled “A Pleated or FoldedCatheter-Mounted Balloon,” which is hereby incorporated herein byreference in its entirety.

This application is related to the following patents or patentapplications, each of which is hereby incorporated herein by referencein its entirety: PCT/US2012/057967, filed on Sep. 28, 2012, U.S.Provisional Application Ser. No. 61/541,765, filed on Sep. 30, 2011,U.S. Provisional Application Ser. No. 61/593,147, filed on Jan. 31,2012, U.S. Provisional Application Ser. No. 61/113,228, filed Dec. 11,2008; U.S. Provisional Application Ser. No: 61/160,204, filed Mar. 13,2009; U.S. Provisional Application Ser. No. 61/179,654, filed May 19,2009; U.S. Patent Application Publication No. 2010/0204560, filed Nov.11, 2009; U.S. Provisional Application Ser. No. 61/334,154, filed May12, 2010; and U.S. patent application Ser. No. 13/106,658, filed May 12,2011.

BACKGROUND

Hypertension and other related cardiovascular disorders are major healthconcerns affecting many adults in the developed world. These conditionscan be especially severe for patients with so-called drug-resistanthypertension (e.g., those unable to achieve target blood-pressure valuesdespite multiple drug therapies at their proper doses). Renaldenervation may be used for the treatment of hypertension,cardiovascular disorders, chronic renal diseases, or other relateddiseases or disease states. It is believed renal denervation has animpact on sympathetic renal nerve activity.

Renal denervation can be performed using minimally invasive proceduresthat use balloon-mounted catheters to navigate through blood vessels todeliver treatment to target sites in the blood vessel. Conventionalcatheters have balloons that “bunch up” when pulled or forced throughthe catheter body, often forming tight random non-deterministic folds.This makes insertion through the guide catheter and pull-back into theguide catheter difficult as the nature of the folds greatly increasesthe force required to insert or withdraw the balloon catheter.

SUMMARY

This disclosure describes systems and methods for pleating acatheter-mounted balloon (e.g., by thermal, mechanical, or chemicalmeans), such that the balloon preferentially folds in a predictablepattern along the pleat lines when collapsed and pushed through thecatheter. By fabricating the balloon to fold automatically according topre-determined pleat patterns, the force required to insert or withdrawthe balloon can be greatly reduced, as compared to a non-pleatedballoon, thus lowering the forces required to insert or withdraw aballoon catheter. Additionally or alternatively, the pleats may beconfigured such that inflation of the balloon requires less pressurethan in a typical system, for example, by using looser pleats than inballoons without pre-pleating. The pre-pleating may also permit use of asmaller catheter in some cases. For ease of illustration, embodimentsare discussed in the context of devices, methods, and systems forachieving renal denervation for the treatment of hypertension, othercardiovascular disorders, and chronic renal diseases. Illustrativeembodiments are described in the context of using energy-based devices(e.g., radio-frequency based devices) and methods to reduce renalsympathetic activity in the renal nerves without causing damage tonon-target cells. However, the embodiments may be adapted and applied inother types of applications, including other neuromodulation devices,without departing from the scope of the disclosure.

The systems, devices, and methods described herein can be used to affectneural communication to and from the one or both kidneys to improvecardio-renal function of the patient, such that the kidney continues tofunction in the patient. Thus, renal nerve fibers can be deactivated(permanently or temporarily) without being completely physically severed(e.g., without fully cutting).

In one aspect, a catheter-mounted balloon includes an inflatable chamberdefining a volume expandable from a deflated state to an inflated state,the inflatable chamber having a distal transition portion, a proximaltransition portion, and a cylindrical body portion disposed between thedistal transition portion and the proximal transition portion. Thecylindrical body portion of the inflatable chamber includes a pleat zonehaving a pleat when the inflatable chamber is in the deflated state. Thecatheter-mounted balloon further includes an electrode disposed along awall of the inflatable chamber. The pleat traverses the electrode suchthat the electrode is pleated as well. In one example, the electrode maybe helical around a longitudinal axis of the inflatable chamber.

According to some implementations, the inflatable chamber defines atleast one irrigation aperture to allow fluid to flow from within theballoon to outside the balloon when the balloon is in the inflatedstate. The irrigation aperture is at least partially unobstructed by thepleat when the inflatable chamber is in the deflated state. By avoidingcomplete obstruction of the pleat, these embodiments may reduce thelikelihood of damage to the irrigation aperture shapes and mayfacilitate providing irrigation for the balloon even when the balloon isnot fully inflated. In one example, the at least one irrigation apertureis disposed between the pleat and a side of the electrode.

According to some implementations, the pleat zone having the pleatdefines an opening between a first side of the pleat and a second sideof the pleat when the inflatable chamber is in the deflated state. Suchan opening can reduce the likelihood of pleating the inflatable chambertightly to the point of damaging the material of the inflatable chamber,damaging any electrode pleated along with the inflatable chamber, orrequiring excessive application of pressure to unfold and inflate theinflatable chamber.

In some implementations, the pleat extends at least partially into theproximal transition portion of the inflatable chamber. For example, atleast a portion of the pleat can be substantially parallel to alongitudinal axis of the cylindrical body portion of the inflatablechamber when the inflatable chamber is in the deflated state.Additionally or alternatively, at least a portion of the pleat can be aspiral around the longitudinal axis of the cylindrical body portion whenthe inflatable chamber is in the deflated state. Additionally oralternatively, at least a portion of the pleat is a substantiallyzig-zag pattern along the longitudinal axis of the cylindrical bodyportion when the inflatable chamber is in the deflated state. As yetanother additional or alternative example, at least a portion of thepleat is substantially parallel to an edge of the electrode.

The inflatable chamber may be collapsible along the pleat in response toa decrease in the volume of the inflatable chamber as the inflatablechamber is deflated from the inflated state to the deflated state.

In certain implementations, the diameter of the cylindrical body portionof the inflatable chamber is in any of the ranges between about 0.01inches and about 0.03 inches, between about 0.01 inches and about 0.015inches, or between about 0.015 inches and about 0.019 inches, when theinflatable chamber is in the deflated state. In certain implementations,the diameter of the cylindrical body portion of the inflatable may beless than about 0.01 inches when the inflatable chamber is in thedeflated state.

According to another aspect, a catheter includes a pleatedcatheter-mounted balloon as described herein, and a guidewire fordelivering the catheter-mounted balloon to an intravascular treatmentsite, while the inflatable chamber of the delivered catheter-mountedballoon is in the deflated state.

In yet another aspect, an energy-based system is provided. The systemcomprises a nerve modulation device including a balloon as describedherein positioned in a vicinity of neural fibers that innervate a kidneyof a patient, where the energy-based device is configured to alterneural communication to and from the kidney.

In yet another aspect, a method is provided for performing a renalneuromodulation procedure to treat a heat-related condition using acatheter-mounted balloon, a catheter, or a energy-based system asdescribed herein.

This description may use the phrases “in embodiments,” “in someembodiments,” or “in certain embodiments,” which may each refer to oneor more of the same or different embodiments in accordance with thepresent disclosure.

As used herein, the terms proximal and distal include a direction or aposition along a longitudinal axis of a catheter or medical instrument.The term “proximal” includes the end of the catheter or medicalinstrument closer to the operator, while the term “distal” includes theend of the catheter or medical instrument closer to the patient. Forexample, a first point is proximal to a second point if it is closer tothe operator end of the catheter or medical instrument than the secondpoint. The term “operator” includes any medical professional (e.g.,doctor, surgeon, nurse, or the like) performing a medical procedureinvolving the use of aspects of the present disclosure described herein.

Embodiments can include one or more of the following advantages.

A balloon that is fabricated to fold according to pre-determined pleatpatterns can be designed to fold into a substantially uniform tubularshape, which can lead to a reduction in the force required to insert orwithdraw the balloon. The tightness of pleats can be arranged to allow apleat to retain an opening between its two sides when the balloon isdeflated, and by so doing, reduce the pressure required for inflatingthe balloon below that required for balloons with tighter pleats.Compared with unpleated balloons, balloons pleated to fold in apreferential configuration can be compatible with a wider range of guidecatheters having smaller inner diameters and less lubricious innercatheter surfaces, resulting in smaller punctures duringminimal-invasive surgery and shorter recovery times.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects and advantages will be apparent uponconsideration of the following detailed description, taken inconjunction with the accompanying drawings, in which like referencecharacters refer to like parts throughout, and in which:

FIG. 1A is a side view of an illustrative catheter-mounted balloon;

FIG. 1B is a cross-section of the balloon in FIG. 1A when thecatheter-mounted balloon is in the inflated state;

FIG. 1C is a cross-section of the balloon in FIG. 1A when thecatheter-mounted balloon is in the deflated state;

FIG. 2A is a perspective cross-section view of an inflatable chamber ofa catheter-mounted balloon with three pleat zones;

FIG. 2B is a cross-section of the inflatable chamber in FIG. 2A;

FIGS. 3 to 7 are cross-sections of example catheter-mounted balloonswith pleats;

FIGS. 8 to 11 are side views of example pleating patterns ofcatheter-mounted balloons with pleats;

FIG. 12A is a schematic representation of an energy-delivery system forproviding renal neuromodulation according to some embodiments;

FIG. 12B illustrates an energy delivery device in use within a renalartery according to some embodiments; and

DETAILED DESCRIPTION

To provide an overall understanding of the systems, devices, and methodsdescribed herein, particular embodiments of the present disclosure aredescribed herein with reference to the accompanying drawings. However,the disclosed embodiments are merely examples of the disclosure and maybe embodied in various forms.

FIG. 1A is a side view of a catheter-mounted balloon 300 without pleats.Balloon 300 is shown in an inflated state, secured to an elongate member(which may be a catheter shaft) 310. FIG. 1B is a correspondingcross-section 320 of balloon 300 when balloon 300 is expanded or in aninflated state, and FIG. 1C is a cross-section 330 of balloon 300 whenballoon 300 is collapsed or in a deflated state. Cross-sections 320 and330 are taken at the anterior-posterior axis 340 shown in FIG. 1A.

Balloon 300 includes an inflatable chamber 301 defining a volumeexpandable from a deflated state to an inflated state, and one or moreelectrodes 308 for providing treatment intravascularly to varioustreatment sites, including for providing an energy signal to renalnerves within the renal artery to achieve renal denervation. In theexample of balloon 300, the electrode 308 is a single helical electrodedisposed on a wall of the balloon. However, any suitable electrode,including any non-helical electrode (e.g., a point-by-point electrode),may be used. In some embodiments, the electrode 308 is a rigid electrodethat does not fold along with the balloon.

Inflatable chamber 301 includes a distal transition portion 302, acylindrical body portion 304, and a proximal transition portion 306.Distal transition portion 302 and proximal transition portion 306 arefrustoconical shapes that taper inwardly away from cylindrical bodyportion 304. In this embodiment, electrode 308 is in a helical or spiralconfiguration around a longitudinal axis of cylindrical body portion 302of inflatable chamber 301. The helical shape of electrode 308 canincrease the likelihood of delivery of RF energy to nerves that are notuniformly distributed around a circumference of a renal artery. Itshould be appreciated, however, that, without departing from the scopeof the present disclosure, electrode 308 may take on any suitable shapeor configuration. Additionally or alternatively, more than one electrodemay be disposed on the inflatable chamber 301.

Electrode 308 delivers energy to a tissue or vascular region wheninflatable chamber 301 is in the inflated state and in contact with oris nearly in contact with the tissue or vascular region. In someembodiments, at least one irrigation aperture (not shown in FIGS. 1A-1C)is defined by cylindrical body portion 302 to facilitate fluid flow fromwithin inflatable chamber 301 to outside inflatable chamber 301 wheninflatable chamber 301 is in the inflated state. Irrigation through oneor more irrigation apertures can provide cooling of the wall ofinflatable chamber 301, electrode 308, and/or tissue in the vicinity ofthe electrode 308 during treatment.

In general, balloon 300 is delivered through a guide catheter (notshown) to a vessel such as a renal artery, where balloon 300 is pushedout from the guide catheter to be placed in proximity to a vascular wallat a treatment site. Once balloon 300 is in position, fluid is pumpedfrom a reservoir (not shown) into inflatable chamber 301 from proximaltransition portion 306 in a closed loop or an open loop configuration.For example, saline may be pumped under constant flow through anirrigation lumen (not shown) to cause inflatable chamber 301 to expandor inflate until an external wall (or a portion thereof) of inflatablechamber 301 makes contact with an inner wall of the vessel. Once fullyinflated, inflatable chamber 301 may assume the shape of cross-section320 shown in FIG. 1B, and electrode 308 on the inflatable chamber 301may assume the helical configuration shown in FIG. 1A. Energy isdelivered to electrode 308, which may be coupled to a conductive guidewire (not shown). Once the energy delivery process terminates, fluidflow is stopped, and inflatable chamber 301 collapses into the deflatedstate. Deflated balloon 300 is then pulled back into the catheter andretrieved from the treatment site.

FIG. 1C shows an example of a cross-section 330 of balloon 300, whenballoon 300 is in a deflated or collapsed state, for example, whenforced through a guide catheter. It should be appreciated that, withoutpleats to guide preferential folding of balloon 300, the cross-section330 shown in FIG. 1C is illustrative, as the cross-section 300 may varyconsiderably each time the balloon 300 is in the deflated or collapsedstate. As fully or partially deflated balloon 300 is pushed or pulledthrough the guide catheter, depending on the shape of inflatable chamber301, and material properties of inflatable chamber 301 and electrode308, balloon 300 may tightly or loosely fold onto itself and “bunch up,”thus requiring a large force to insert or withdraw the balloon 300relative to the guide catheter. During balloon deployment, the distalend of the guide catheter may be protected with a silicon seal thatprovides additional resistance to movement of the balloon.

To exert more control over the shape and configuration of balloon 300 ina fully or partially deflated state so balloon 300 may more easily moveout of and into a guide catheter, pleating (e.g., thermal pleating) maybe applied to balloon 300 during the manufacturing process, such thatballoon 300 folds in preferential configurations when pushed through theguide catheter, and collapses in similar preferential configurationswhen pulled back into the guide catheter. By pleating and allowingballoon 300 to fold according to pre-determined pleat patterns, theforce required to insert or withdraw the balloon through the cathetercan be greatly reduced, thus facilitating successful deployment ofballoon 300.

Inflatable chamber 301 may comprise a layer of shape memory materialsuch as shape-memory polymers which can retain or recover differentshapes and can transition easily between those shapes with minimalforce. Such shape restoration properties help retain preferential shapeconfiguration after inflation of balloon 300 and subsequent deflationprocesses. Examples of shape memory materials include polyurethane-basedshape memory polymers, and polyether foams.

FIG. 2A is a perspective cross-section of an illustrative pleatedinflatable chamber 335, which includes a proximal transition portion 336and a cylindrical body portion 337. Inflatable chamber 335 can be used,for example, in place of inflatable chamber 301 in FIG. 1A. For clarityof illustration, only a fraction of cylindrical body portion 337 isshown in FIG. 2A. FIG. 2B shows a corresponding cross-sectional view ofthe inflatable chamber 335 in FIG. 2A. In both figures, pleatedinflatable chamber 335 is in a deflated or partially deflated state.Cylindrical body portion 337 includes three longitudinal pleats 340 a,340 b and 340 c. As used herein, a “pleat” includes a fold or a bend ofa surface, and a “pleat zone” includes a portion of the surface thatincludes the pleat. For example, pleat 340 a is included in pleat zone343 a bordered by folds 341 and 345. Pleat zone 343 a includes pleat 340a as well as a first side 342 of pleat 340 a and a second side 344 ofpleat 340 a. In some embodiments, inflatable chamber 301 is collapsiblealong the pleats in response to a decrease in the volume of inflatablechamber 301 as inflatable chamber 301 is deflated from the inflatedstate to the deflated state.

In the pleated inflatable chamber 335 shown in FIG. 2A, pleat zone 343 adefines an opening 346 between first side 342 of pleat 343 a and secondside 344 of pleat 343 a when the balloon is in a fully or partiallydeflated state. A loose pleat in a pleat zone with an opening (e.g.,pleat zone 343 a with opening 346) allows the application of a lowerfluid pressure when a catheter-mounted balloon is inflated. For example,a loosely pleated balloon may be properly inflated when the fluidpressure is in the range from about 5 psi to about 100 psi, or from 10psi to 50 psi, while a tightly pleated balloon (e.g., a balloon pleatedwith two-layer gaps) may require a fluid pressure in the range fromabout 100 psi to about 400 psi. Additionally or alternatively, loosepleating can reduce the likelihood of damage to the mechanical integrityof the balloon.

In addition, depending on the material composition of inflatable chamber335, the manufacturing process which may involve thermal treatment, andthe operational pressure of the inflatable chamber 335, pleats 340 a,340 b, 340 c within inflatable chamber 335 may maintain their shapewithin the normal operational pressure range of the inflatable chamber335. In other words, the pleats 340 a, 340 b, 340 c can self-recover andfold back into a preferential configuration to facilitate the retrievalof the balloon 300 back into the guide catheter.

As compared to a balloon without pleats, pleating of inflatable chamber335 of balloon 300 reduces the circumferential length of the inflatablechamber 335 when the inflatable chamber 335 is in a fully or partiallydeflated state. This reduced circumferential length can facilitate, forexample, the use of smaller diameter guide catheters which can beaccommodated by smaller punctures during minimally invasive surgery, andconsequently can reduce patient recovery time. In some embodiments, thediameter of a pleated cylindrical body portion 337 of inflatable chamber335 is less than about 0.025 inch when inflatable chamber 335 is in thedeflated state. In certain embodiments, the diameter of pleatedcylindrical body portion 337 of inflatable chamber 335 is less thanabout 0.019 inch when inflatable chamber 335 is in the deflated state.In some embodiments, the diameter of pleated cylindrical body portion337 of inflatable chamber 335 is in any of the ranges between about 0.01inches and about 0.015 inches, between about 0.01 inch and 0.03 inches,between about 0.015 inches and about 0.019 inches when the inflatablechamber is in the deflated state. In some embodiments, the diameter ofpleated cylindrical body portion 337 of inflatable chamber 335 is lessthan about 0.01 inch when inflatable chamber 335 is in the deflatedstate.

Pleats 343 a, 343 b, and 343 c are sharp folds that can be viewed as theintersecting line between two surfaces. In some embodiments, pleats 343a, 343 b, and 343 c may be soft, with substantially round corners thatcan bend and fold into a predetermined configuration. Soft pleats areadvantageous, for example, in embodiments wherein one or more pleats 343a, 343 b, 343 c traverse an electrode (e.g., electrode 118 in FIG. 1A)such that the electrode is pleated. For example, as compared to sharppleats, soft pleats may be useful for reducing the likelihood thatelectrical properties of the traversed electrode will be compromised bythe pleat while still facilitating the use of reduced force to insertand withdraw a balloon within a guide catheter.

Although three pleats are shown in FIGS. 2A and 2B, in variousembodiments, a catheter-mounted balloon may include any suitable numberof pleats, pleat shapes, pleat sizes, and pleat patterns.

FIGS. 3-7 are cross-sections of exemplary pleated inflatable chambers,with each inflatable chambers shown in a deflated state.

FIG. 3 is a cross-sectional view of an inflatable chamber with tworadially symmetrical pleats, which may facilitate rotation of acatheter-mounted balloon through a guide catheter (e.g., a guidecatheter having a lubricious inner surface and/or a guide catheterhaving grooves complementary to the pleat pattern). In the examplesshown in FIGS. 2A and 2B, pleats extend longitudinally across thecylindrical body portion 337. In some embodiments, however, the pleatsmay be a spiral around the longitudinal axis of the inflatable chamberwhen the inflatable chamber is in a fully or partially deflated state,and/or may form a substantially zig-zag pattern along the longitudinalaxis of the cylindrical body portion when the inflatable chamber is inthe deflated state.

FIG. 4 is a cross-sectional view of an inflatable chamber with threeradially symmetrical pleats. As compared to pleats 340 a, 340 b, and 340c in FIGS. 2A and 2B which are in adjacent pleat zones, pleats 410 a,410 b, and 410 c shown in FIG. 4 are located in respective pleat zones420 a, 420 b, and 420 c spaced apart on the surface of the inflatablechamber.

FIG. 5 is a cross-sectional view of an inflatable chamber with fourpleats, where the orientation of the pleats is configured so thecircumferential shape of the inflatable chamber is circular.

FIG. 6 is a cross-sectional view of an inflatable chamber with fivepleats. In general, any suitable number of pleats may be set (e.g.,thermally set) into the inflatable chamber of a catheter-mountedballoon.

FIG. 7 illustrates an inflatable chamber with four soft pleats. Asdescribed herein, soft pleats may be used when a pleat traverses anelectrode disposed on the inflatable chamber, where traversal of theelectrode by the pleat causes the electrode to be pleated as well and,as compared to a sharp pleat, the soft pleat is less likely to impactthe electrical properties and/or structural integrity of the electrode.

FIGS. 8-11 are side views of example pleating patterns of pleatedballoons, each balloon including one or more pleats, one or moreelectrodes and, optionally, defining one or more irrigation apertures.

Referring to FIG. 8, a balloon 800 includes an inflatable chamber 801and an electrode 808, with electrode 808 disposed (e.g., diagonallydisposed) on inflatable chamber 801. In the illustrated example,inflatable chamber 801 includes two pleats 810 and 820, each of whichextends across electrode 808. It should be appreciated, however, one ofpleats 810 and 820 can be arranged to extend across electrode 808 whilethe other of pleats 810 and 820 does not extend across electrode 808.Additionally or alternatively, it should be appreciated that inflatablechamber 801 can includes fewer or greater pleats without departing fromthe scope of the present disclosure.

In the deflated state, the cross-section of inflatable chamber 801 maybe as shown in FIG. 3. Inflatable chamber 801 includes a proximaltransition portion 802, a cylindrical body portion 804, and a distaltransition portion 806. In this example, pleats 810 and 820 extendlongitudinally along cylindrical body portion 804, from proximaltransition portion 802 to distal transition portion 806.

In this example, irrigation apertures 830 flank both sides of electrode808 to cool the electrode during energy delivery. In some embodiments,irrigation apertures 830 are placed and designed so that, in a fully orpartially deflated state of inflatable chamber 801, pleats 810 and 820do not fully obstruct irrigation apertures 830 and, thus, do notentirely block fluid flow through irrigation apertures 830, reducing thelikelihood of pressure buildup within inflatable chamber 801. In someembodiments, irrigation apertures 830 may be partially blocked by apleat when the inflation chamber 801 is in the deflated state.

Pleats 810 and 820 may fold in pre-determined directions. In thisexample, pleat 810 and pleat 820 may fold to the right, in direction840, and no irrigation apertures are disposed immediately next to pleats810 and 820.

Referring to FIG. 9, a balloon 900 includes an inflatable chamber 901and an electrode 908. Inflatable chamber 901 includes three pleats 910,920, and 930, and electrode 908 is disposed on inflatable chamber 901such that each pleat 910, 920, and 930 extends across electrode 908. Ina fully or partially deflated state, the cross-section of inflatablechamber 901 may be as shown in FIG. 2B or FIG. 3. In the example shownin FIG. 9, pleats 910, 920, and 930 extend longitudinally along thecylindrical body portion 904 and also into proximal transition portion902 of inflatable chamber 901. The full or partial extension of pleats910, 920, and 930 into proximal transition portion 902 may facilitatewinding of inflatable chamber 901 and electrode 908 when balloon 900 ispulled back into a guide catheter after energy delivery. Additionally oralternatively, pleats 815 and 825 may be included in proximal portion902 to facilitate the folding of balloon 900. Additionally oralternatively, one or more pleats may extend into distal portion 906.

Referring now to FIG. 10, a balloon 1000 includes an inflatable chamber1001 and an electrode 1008. Inflatable chamber 1001 includes six pleats1010, and electrode 1008 is disposed on inflatable chamber 1001 suchthat pleats 1010 do not cross electrode 1008. Pleats 1010 and,optionally, irrigation apertures flank both sides of electrode 1008.

Referring to FIG. 11, a balloon 1100 includes an inflatable chamber 1101and an electrode 1108. Inflatable chamber 1101 includes four crinkledpleats 1110, and electrode 1108 is disposed on inflatable chamber 1101such that pleats 1110 flank both sides of electrode 1108. In certainembodiments, inflatable chamber 1101 defines irrigation apertures. Insome embodiments, at least a portion of each pleat 1110 is asubstantially zig-zag pattern along the longitudinal axis of acylindrical body portion of inflatable chamber 1101 when inflatablechamber 1101 is in the deflated state. In certain embodiments, at leasta portion of one pleat 1110 is a spiral around a longitudinal axis ofthe cylindrical body portion when inflatable chamber 1101 is in thedeflated state. In general, any suitable number of irrigation aperturesmay be included, at any reasonable positions and pleats 1110 may befolded in different orientations to avoid blocking the irrigationapertures during fluid flow.

The systems, devices, methods, electrodes, inflatable chambers, andballoons described above may be incorporated into a system to provide,for example, renal denervation treatment.

FIG. 12A illustrates an energy-delivery system 100 for providing renalneuromodulation according to some embodiments. The system 100 includesan energy delivery device 110, energy generator 120, and display 150.The energy delivery device 110 can be, for example, any of the energydelivery devices described herein. In the example of system 100, theenergy-delivery device 110 is a balloon catheter sized for intravascularplacement to deliver energy to neural fibers along a renal artery tomodulate sympathetic renal nerve activity.

The system 100 includes a user interface device 150 for communicatinginput and output information to the operator of the system. In someembodiments, the user interface device 150 is a display device. Thedisplay can be, for example, a touch screen interface for user input,and can display instructional messages and procedural feedback, such aspower delivered, impedance, and remaining treatment time. In someembodiments, the user interface device 150 communicates to the operatorwarning messages.

The system 100 includes energy generator 120 which provides an energysignal the energy delivery device 110. The energy generator 120 includescontrol circuitry and memory for controlling the operation of thesystem. The energy generator 120 can be coupled to the energy deliverydevice (and/or to the user interface device 150) by wired or wirelesslink. In this example, the energy generator 120 is placed external tothe patient.

Although shown separately from the user interface device 150, the energygenerator 120 may be integrated with the user interface device 150 in asingle housing. In some embodiments, the energy generator 120 includesmemory, processing circuitry, firmware, and hardware for programming orcontrolling the system 100 to provide treatment to tissue. The energygenerator 120 can provide any suitable type of energy signal to theenergy delivery device 110. In some embodiments, renal neuromodulationmay be achieved via generation and/or application of thermal energy tothe target neural fibers, such as through application of a an energyfield, including, electromagnetic energy, radio frequency, ultrasound(including high-intensity focused ultrasound), microwave, light energy(including laser, infrared and near-infrared) etc., to the target neuralfibers. For example, thermally-induced renal neuromodulation may beachieved via delivery of a pulsed or continuous thermal energy field tothe target neural fibers. The energy field can be sufficient magnitudeand/or duration to thermally induce the neuromodulation in the targetfibers (e.g., to heat or thermally ablate or necrose the fibers).

Without wishing to be bound by theory, it is believed that thermalablation or non-ablative alteration of the target neural fibers at leastpartially denervates the kidney innervated by the neural fibers viaheating. Thermal heating mechanisms for neuromodulation include boththermal ablation and non-ablative thermal alteration or damage (e.g.,via sustained heating or resistive heating). Thermal heating mechanismsmay include raising the temperature of target neural fibers above adesired threshold to achieve non-ablative thermal alteration, or above ahigher temperature to achieve ablative thermal alteration. For example,the target temperature can be above body temperature (e.g.,approximately 37 degrees C.) but less than about 45 degrees C. fornon-ablative thermal alteration, or the target temperature can be about45 degrees C. or higher for the ablative thermal alteration. The lengthof exposure to thermal stimuli may be specified to affect an extent ordegree of efficacy of the thermal neuromodulation. For example, theduration of exposure can be as short as about 5, about 10, about 15,about 20, about 25, or about 30 seconds, or could be longer, such asabout 1 minute, or even longer, such as about 2 minutes. Additionally oralternatively, the exposure can be intermittent or continuous to achievethe desired result.

The energy delivery device 110 includes a catheter-mounted balloon 116including an inflatable chamber 117 and an electrode 118 disposed oninflatable chamber 117. The catheter-mounted balloon 116 is disposed onan elongate member 128, which is a catheter. Inflatable chamber 117defines irrigation apertures 138 and is, in some embodiments, aninflatable balloon.

Catheter-mounted balloon 116 is delivered intravascularly via a guidecatheter (not shown) and along a guidewire 140 in a folded configurationand is then inflated by flowing fluid (e.g., saline solution) to raisethe pressure in inflatable chamber 117 and cause inflatable chamber 117and electrode 118 to unfold. Inflatable chamber 117 may be made ofnon-elastic/non-compliant material or of compliant/elastic. Materialsfor a non-compliant inflatable chamber 117 include, without limitation,polyethylene, polyethylene terephthalate, polypropylene, cross-linkedpolyethylene, polyurethane, and polyimide. Materials for a compliantinflatable chamber 117 include, without limitation, nylon, silicon,latex, and polyurethane.

Inflatable chamber 117 can be any suitable size. In some embodiments,the diameter (e.g., a diameter of a cylindrical body portion) ofinflatable chamber 117 is about 4 mm to about 10 mm. In certainembodiments, the inflatable chamber 117 has a diameter (e.g., a diameterof a cylindrical body portion) of about 5 mm, about 6 mm, or about 7 mm.The axial length of the inflatable chamber 117 can range from about 10mm to about 50 mm. In some embodiments, the axial length of theinflatable chamber 117 is about 15 mm to about 30 mm. In someembodiments, the length of the inflatable element is about 20 mm. Incertain embodiments, the axial length of the cylindrical intermediateportion of inflatable chamber 117 is between about 1 cm and about 4 cm.In some embodiments, the axial length of the cylindrical intermediateportion of the inflatable chamber 117 is about 20 mm and the diameter isabout 5 mm to about 7 mm.

The electrode 118 (e.g., a single helical electrode) is disposed oninflatable chamber 117 such that inflatable chamber 117 serves as asubstrate for electrode 118. In some embodiments, electrode 118 includesa helical section that makes about 0.5 revolutions to about 1.5revolutions around inflatable chamber 117. Electrode 118 can be formed,for example, by depositing a conductive material on the exterior wall ofthe inflatable chamber 117, following depositing an insulation materialon sections of the inflatable chamber 117, leaving electrode 118 as theonly substantially conductive surface on the portion of thecatheter-mounted balloon 116 that is expected to come into contact withtissue.

In some embodiments, portions of electrode 118 are covered by insulationmaterial, forming a plurality of discrete conductive sections onelectrode 118. In such embodiments, a single conductor can be used tocreate a number of discrete burn zones following a helical path alongand around a vessel wall. In use, these embodiments create adiscontinuous helical burn pattern formed by a plurality of discreteburn areas in the tissue. The helical burn pattern can be formed duringa single treatment session, and does not require the device be moved tocreate the plurality of discrete burn areas. Applicants have previouslydescribed mechanisms for generating various electrode patterns for usein renal neuromodulation in commonly owned and co-pendingPCT/US2012/057967, filed on Sep. 28, 2012, which has been incorporatedherein by reference in its entirety. Other electrodes (includingprobe-mounted electrodes) located within or outside of inflatablechamber 117 can additionally or alternatively be used.

Irrigation apertures 138 include one or more holes (which may have anysuitable size or shape) for providing protective irrigation tonon-target tissue and/or cooling the electrode(s) in connection withrenal neuromodulation. Irrigation apertures 138 can be defined along anysuitable location on the inflatable chamber 117, such as along thecontours of and outside of electrode 118, within the electrode(s) 118,or elsewhere on inflatable chamber 117.

The system 100 can include a fluid reservoir (not shown) in fluidcommunication with the energy delivery device 110 via an irrigationline. Irrigation fluid from the fluid reservoir is delivered by a pumpintegrated with the energy generator 120, and controlled by the same, tothe energy delivery device 110 through an irrigation line. Theirrigation fluid then flows out of the inflatable chamber 117 throughthe irrigation apertures 138. The energy generator 120 controlsoperation of the pump to control the flow rate of the fluid from thereservoir into the inflatable chamber 117. In some embodiments, the pumpcontinuously pumps at a constant flow rate such that the flow iscontinuous from the reservoir. In certain embodiments, the pump isoperated in an open loop constant flow configuration in which the pumprate is controlled by an over-pressure condition sensed by a pressuresensor (not shown), in which case the energy delivery is terminated, thepump is turned off, and an over-pressure condition reported to theoperator. The pump is typically operated for a period of time whichencompasses the delivery of the energy and turned off shortly after theconclusion of the procedure or if the pressure sensor senses anundesirable condition, as discussed in further detail below.

The pressure sensor measures the operating pressure within inflatablechamber 117, and may be adapted to determine if the pressure rises aboveor below threshold limits. The pressure can elevate if, for example, oneor more of irrigation apertures 138 become blocked, preventing fluidfrom passing out of inflation chamber 117, which can reduce cooling ofelectrode 118. The memory of energy generator 120 can includecomputer-executable instructions, executable by control circuitry ofenergy generator 120, to suspend (e.g., pause or terminate) delivery ofenergy to electrode 118, and to shut off the fluid pump if the fluidpressure rises above an established limit. In some embodiments, thepressure measured at the pressure sensor is driven by the fluid flowrate and the series sum of the fluid resistance of all of the elementsin the fluid path. The choice of fluid flow rate may be affected by therequired cooling rate and by the amount of irrigant fluid that can betolerated by the patient.

The operating pressure within inflatable chamber 117 may be affected bythe fluid flow, the number of apertures 138, and cross sections ofirrigation apertures 138. The distribution, number, and cross section ofirrigation apertures 138 will be a function of the flow rate ofirrigation fluid provided by the pump of energy generator 120, theconfiguration of electrode 118, the intended operating pressure, and themaximum desired exit velocity for the irrigation fluid at the treatmentsite.

Device 110 can include at least one marker 127 disposed on cathetershaft 128 such that the marker is within inflatable chamber 117. In someembodiments, marker 127 is a radio opaque marker (e.g., a markerincluding one or more of platinum and platinum-iridium). In certainembodiments, marker 127 also includes features viewable underfluoroscopy that allow, for example, for visualization of rotationalorientation of marker 127. This can facilitate location and/orrealignment of the inflatable chamber 117 and electrode 118 by theoperator within the renal artery.

Referring to FIG. 12B, an exemplary method is shown for using system 100for a renal denervation procedure by application of RF energy to tissuein a renal artery. The method described herein can be carried out byother systems and by other energy-delivery devices, such as the otherdevices described herein. The energy-delivery device 110 is positionedin a renal artery using percutaneous access through a femoral artery.The inflatable element is delivered into the renal artery 1000 in acollapsed configuration (not shown). Fluid from the fluid reservoir ispumped (e.g., in an open loop control configuration, under constantflow) through the irrigation line and into the inflatable chamber 117 bythe pump controlled by the energy generator 120 (FIG. 12A). Fluid flowinflatable chamber 117 causes inflatable chamber 117 to expand. Device110 in FIG. 12B is in a delivered, or expanded, configuration withinrenal artery 1000. The tunica intima 1001 is surrounded by the tunicamedia 1002, which is in turn surrounded by adventitial tissue 1003.Tissue renal nerves 1004 are shown within the adventitial, and somerenal nerves (not shown) are located within the tunica media.

The fluid continually passes through apertures 138 in the inflatablechamber 117 as the fluid is replaced with new fluid from the fluidreservoir. Once fully expanded, electrode 118 on inflatable chamber 117assumes a helical configuration as shown in FIG. 12A. RF energy isdelivered to electrode 118 on the inflatable chamber 117. Energygenerator 120 controls the parameters of the RF energy being deliveredto the electrode 118 via conductive material carried by the cathetershaft 128. In general, the RF signal characteristics are chosen to applyenergy to depths at which the renal nerves are disposed to ablate therenal nerves. In general, the power is selected to ablate a majority ofthe renal nerves adjacent to where the device is positioned within therenal nerve. In some embodiments the tissue is ablated to a depth ofbetween about 3 mm to about 7 mm from the tissue closest to the devicein the renal artery.

Tissue treated by the RF energy via the helical electrode is shown asregions 1005, delineated by a dashed line. As illustrated, a region oftreated tissue 1005 adjacent to the conductor 118 includes nerve 1004.The device can be used in monopolar mode with a return electrodepositioned somewhere on the patient's skin. However, it can also be usedin bipolar mode without deviating from the scope of the disclosure.

While several embodiments of the disclosure have been shown in thedrawings and/or discussed herein, it is not intended that the disclosurebe limited thereto, as it is intended that the disclosure be as broad inscope as the art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. A catheter-mounted balloon comprising: aninflatable chamber defining a volume expandable from a deflated state toan inflated state, the inflatable chamber having a distal transitionportion, a proximal transition portion, and a cylindrical body portiondisposed between the distal transition portion and the proximaltransition portion, the cylindrical body portion includes a pleat zonehaving a pleat when the inflatable chamber is in the deflated state; andan electrode disposed along a wall of the inflatable chamber, whereinthe pleat traverses the electrode such that the electrode is pleated. 2.The balloon of claim 1, wherein the inflatable chamber defines at leastone irrigation aperture to allow fluid to flow from within theinflatable chamber to outside the inflatable chamber when the inflatablechamber is in the inflated state.
 3. The balloon of claim 2, wherein theat least one irrigation aperture is at least partially unobstructed bythe pleat when the inflatable chamber is in the deflated state.
 4. Theballoon of claim 2, wherein the at least one irrigation aperture isdisposed between the pleat and a side of the electrode.
 5. The balloonof claim 1, wherein the pleat zone having the pleat defines an openingbetween a first side of the pleat and a second side of the pleat whenthe inflatable chamber is in the deflated state.
 6. The balloon of claim1, wherein the electrode is helical around a longitudinal axis.
 7. Theballoon of claim 1, wherein the pleat extends at least partially intothe proximal transition portion of the inflatable chamber.
 8. Theballoon of claim 1, wherein the inflatable chamber is collapsible alongthe pleat in response to a decrease in the volume of the inflatablechamber as the inflatable chamber is deflated from the inflated state tothe deflated state.
 9. The balloon of claim 1, wherein the inflatablechamber comprises a layer of shape memory material.
 10. The balloon ofclaim 1, wherein the pleat is substantially parallel to a longitudinalaxis of the cylindrical body portion when the inflatable chamber is inthe deflated state.
 11. The balloon of claim 1, wherein at least aportion of the pleat is a spiral around a longitudinal axis of thecylindrical body portion when the inflatable chamber is in the deflatedstate.
 12. The balloon of claim 1, wherein at least a portion of thepleat is a substantially zig-zag pattern along the longitudinal axis ofthe cylindrical body portion when the inflatable chamber is in thedeflated state.
 13. The balloon of claim 1, wherein at least a portionof the pleat is substantially parallel to an edge of the electrode. 14.The balloon of claim 1, wherein at least one of the distal transitionportion and the proximal transition portion of the inflatable chamber isfrustoconically shaped.
 15. A catheter comprising: a balloon includingan inflatable chamber defining a volume expandable from a deflated stateto an inflated state, the inflatable chamber having a distal transitionportion, a proximal transition portion, and a cylindrical body portiondisposed between the distal transition portion and the proximaltransition portion, the cylindrical body portion includes a pleat zonehaving a pleat when the inflatable chamber is in the deflated state, andan electrode disposed along a wall of the inflatable chamber, whereinthe pleat traverses the electrode such that the electrode is pleated;and a guidewire for delivering the balloon to an intravascular treatmentsite, while the delivered inflatable chamber is in the deflated state.16. The catheter of claim 15, wherein the inflatable chamber of theballoon comprises a layer of shape memory material.